//随机产生一个长度为5的验证码,验证码前四位是大写字母或者小写字母,最后一位是0-9的数字
import java.util.Random;
public class A12{
	public static void main(String[] args){
		char[] character = new char[52];
		for(int i = 0;i < character.length;i++){
			if(i < 26){
				character[i] = (char)(97+i);
			}else{
				character[i] = (char)(65+i-26);
			}
		}
		Random r = new Random();
		String sum = "";
		for(int i = 0;i < 4;i++){
			int randomIndex = r.nextInt(character.length);
			sum += character[randomIndex];
		}
		int number = r.nextInt(10);
		sum += number;
		System.out.println(sum);
	}
}